3-Oxa prostaglandin B-type compounds

ABSTRACT

This invention is a group of 3- and 4-oxa PG-type compounds, and processes for making them. These compounds are useful for a variety of pharmacological purposes, including anti-ulcer, inhibition of platelet aggregation, increase of nasal patency, labor inducement at term, and wound healing.

United States Patent [191 Nelson [4 1 Nov. 25, 1975 3-OXA PROSTAGLANDIN B-TYPE COMPOUNDS [75] Inventor: Norman A. Nelson, Galesburg,

Mich.

[73] Assignee: The Upjohn Company, Kalamazoo,

Mich.

[221 Filed: Apr. 17, 1974 [21] Appl. No.: 461,603

Related US. Application Data [63] Continuation of Ser. No. 332,079, Feb. 13. 1973, abandoned, which is a continuation-in-part of Ser. No. 47,169, June 17, 1970, abandoned.

[30] Foreign Application Priority Data July 29, 1969 United Kingdom 38073/69 [52] US. Cl... 260/468 D; 260/211 R; 260/247.2 R; 260/268 R; 260/293.65; 260/306.2; 260/410; 260/424.4; 260/439 R; 260/448 R; 260/488 R; 260/501.1; 260/501.l5; 260/50l.17;

[51] Int. C13,. C07C 61/38; C07C 69/74 [58] Field of Search 260/468 D, 514 D [56] References Cited FOREIGN PATENTS OR APPLICATIONS 2,036,471 12/1974 Germany 260/468 Primary Examiner-Robert Gerstl Attorney, Agent, or FirmMorris L. Nielsen [57] ABSTRACT 38*Claims, No Drawings 3-OXA PROSTAGLANDIN B-TXPE COMPOUNDS CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation of my copending application Ser. No. 332,079, filed Feb. 13, 1973, now abandoned, which was a continuation-in-part of my then copending application Ser. No. 47,169, filed June 17, 1970, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to compositions of matter, and to methods and intermediates for producing them. In particular, the several aspects of this invention relate to novel analogs of some of the known prostaglandins, for example, prostaglandin E (PGE prostaglandin E (PGE prostaglandin F (PGF and PFG prostaglandin F (PGF and PGF prostaglandin A (PGA prostaglandin A (PGA prostaglandin B (PGB prostaglandin B (PGB the corresponding PG s, and the dihydro PG derivatives, to novel methods for producing those novel prostaglandin analogs, and to novel chemical intermediates useful in those novel methods.

Each of the above-mentioned known prostaglandins is a derivative of prostanoic acid which has the following structure and atom numbering:

COOH

A systematic name for prostanoic acid is 7-[(2B-octyl)- cyclopent-la-yl]heptanoic acid.

PGE has the following structure:

PGF has the following structure:

PGF has the following structure:

Each of the known prostaglandins PGE PGF a PGF B PGA and PGB has a structure the same as that shown for the corresponding PG compound except that in each, C-5 and C-6 are linked with a cis carbon-carbon double bond. For example, PGE has the following structure:

Vll

Each of the known PG prostaglandins has a structure the same as that of the P6 compounds except that in each, C-17 and C-18 are linked with a cis carboncarbon double bond. For example, PGE has the following structure:

Vlll

Each dihydro derivative of PGE PGF a PGF, PGA,, and PGB has a structure the same as that shown for the corresponding PG compound except that in each, C-13 and C-14 are linked with a carbon-carbon 3 single bond. For example, dihydro'PGE has the following structure:

The prostaglandin formulas mentioned above each have several centers of asymmetry. As drawn, formulas II to [X each represents the particular optically active form of the prostaglandin obtained from certain mammalian tissues, for example, sheet vesicular glands, swine lung, and human seminal plasma, or by reduction or dehydration of a prostaglandin so obtained. See, for example, Bergstrom et al., Pharmacol. Rev. 20, 1 (1968), and references cited therein. The mirror image of each formula represents a molecule of the enantiomer of that prostaglandin. The racemic form of the prostaglandin consists of equal numbers of two types of molecules, one represented by'one of the above formulas and the other represented by the mirror image of that formula. Thus, both formulas are needed to define a racemic prostaglandin. See Nature 212, 38 (1966) for discussion of the stereochemistry of the prostaglandins.

in formulas I-IX, as well as in the formulas given hereinafter, broken line attachments to the cyclopentane ring indicate substituents in alpha configuration, i.e., below the plane of the cyclopentane ring. Heavy solid line attachments to the cyclopentane ring indicate substituents in beta configuration, i.e., above the plane of the cyclopentane ring.

Prostaglandins with carboxyl-terminated side chains attached to the cyclopentane ring in beta configuration are also known. These are derivatives of 8-iso-prostanoic acid which has the following formula:

A systematic name for 8-iso-prostanoic acid is 7-[(2B- octy1)-cyclopent-1B-yl1heptanoic acid.

The side-chain hydroxy at C- in formulas II to [X is in alpha (S) configuration. See Nature 212, 38 (1966) for discussion of the stereochemistry of the prostaglandins.

PGE,, PGE dihydro-PGE and the corresponding PGFQ PGF PGA, and PGE compounds, and their esters, acylates, and pharmacologically acceptable salts, are extremely potent in causing various biological responses. For that reason, these compounds are useful for pharmacological purposes. See, for example, Bergstrom et al., Pharmacol. Rev. 20, 1 (1968), and references cited therein. A few of those biological respnses are systemic blood pressure lowering in the case of the PGE and PGA compounds as measured, for example, in anesthetized (pentobarbital sodium) pentoliniumtreated rats with indwelling aortic and right heart cannulas; stimulation of smooth muscle as shown, for example, by tests on strips of guinea pig ileum, rabbit duodenum, or gerbil colon; potentiation of other smooth muscle stimulants; antilipolytic activity as shown by antagonism of epinephrinednduced mobilization of free fatty acids or inhibition of the spontaneous release of glycerol from isolated rat fat pads; inhibition of gastric secretion in the case of the PGE and PGA compounds as shown in dogs with secretion stimulated by food or histamine infusion; activity on the central nervous system; controlling spasm and facilitating breathing in asthmatic conditions; decreasing blood platelet adhesiveness as shown by platelet-to-glass adhesiveness, and

inhibition of blood platelet aggregation and thrombus formation induced by various physical stimuli, e.g., ar-

terial injury, and various biochemical stimuli, e.g., ADP, ATP, serotonin, thrombin, and collagen; and in the case of the PGE and PGE compounds, stimulation of epidermal proliferation and keratinization as shown when applied in culture to embryonic chick and rat skin segments.

Because of these biological responses; these known prostaglandins are useful to study, prevent, control, or

For example, these compounds, and especially the PGE compounds, are useful in mammals, including man, as nasal decongestants. For this purpose, the compounds are used in a dose range of about 10 g to about 10 mg. per ml. of a pharmacologically suitable liquid vehicle or as an aerosol spray, both for topical application.

The PGE, PGFa PGFB and PGA compounds are useful in the treatment of asthma. For example, these compounds are useful as bronchodi lators or as inhibitors of mediators, such as SRS-A, and histamine which are released from cells activated by an antigen anti body complex. Thus, these compounds control spasm and facilitate breathing in conditions such as,bronchial asthma, bronchitis, bronchiectasis, pneumonia and emphysema. For these purposes, these compounds are administered in a variety of dosage forms, e.g., orally in the form of tablets, capsules, or liquids; rectally in the form of suppositories; parenterally, subcutaneously, or intramuscularly, with intravenous administration being preferred in emergency situations; by inhalation in the form of aerosols or solutions for nebulizers; or by insuf flation in the form of powder. Doses in the range of about 0.01 to 5 mg. per kg. of body weight are used to 1 to 4 times a day, the exact dose depending on the age,

weight, and condition of the patient and on the frequency and route of administration. For the above use these prostaglandins can be combined advantageously with other anti-asthmatic agents, such as sympathomimetics (isoproterenol, phenylephrine, ephedrine, etc.);

xanthine derivatives (theophylline and aminophylline);

and cortico-steroids (ACTH and predinisolone). Regarding use of these compounds see South African Pat. No. 681,055.

The PGE and PGA compounds are useful in mammals, including man and certain useful animals, e.g., dogs and pigs, to reduce and control excessive gastric secretion, thereby reducing or avoiding gastrointestinal ulcer formation, and accelerating the healing of such ulcers already present in the gastrointestinal tract. For this purpose, the compounds are injected or infused intravenously, subcutaneously, or intramuscularly in an infusion dose range about 0.1 ug. to about 500 pg. per kg. of body weight per minute, or in a total daily dose by injection or infusion in the range about 0.1 to about 20 mg. per kg. of body weight per day, the exact dose depending on the age, weight, and condition of the patient or animal, and on the frequency and route of administration.

The PGE, PGFa and PGFp compounds are useful whenever it is desired to inhibit platelet aggregation, to reduce the adhesive character of platelets, and to remove or prevent the formation of thrombi in mammals, including man, rabbits, and rats. For example, these compounds are useful inthe treatment and prevention of myocardial infarcts, to treat and prevent post-operative thrombosis, to promote patency of vascular grafts following surgery, and to treat conditions such as atherosclerosis, arteriosclerosis, blood clotting defects due to lipemia, and other clinical conditions in which the underlying etiology is associated with lipid imbalance or hyperlipidemia. For these purposes, these compounds are administered systemically, e.g., intravenously, subcutaneously, intramuscularly, and in the form of sterile implants for prolonged action. For rapid response, especially in emergency situations, the intravenous route of administration is preferred. Doses in the range about 0.005 to about 20 mg. per kg. of body weight per day are used, the exact dose depending on the age, weight, and condition of the patient or animal, and on the frequency and route of administration.

The PGE, PGFa and PGF compounds are especially useful as additives to blood, blood products, blood substitutes, and other fluids which are used in artificial extracorporeal circulation and perfusion of isolated body portions, e.g., limbs and organs, whether attached to the original body, detached and being preserved or prepared for transplant, or attached to a new body. During these circulations and perfusions, aggregated platelets tend to block the blood vessels and portions of the circulation apparatus. This blocking is avoided by the presence of these compounds. For this purpose, the compound is added gradually or in single or multiple portions to the circulating blood, to the blood of the donor animal, to the perfused body portion, attached or detached, to the recipient, or to two or all of those at a total steady state dose of about 0.001 to mg. per liter of circulating fluid. It is especially useful to use these compounds in laboratory animals, e.g., cats, dogs, rabbits, monkeys, and rats, for these purposes in order to develop new methods and techniques for organ and limb transplants.

PGE compounds are extremely potent in causing stimulation of smooth muscle, and are also highly active in potentiating other known smooth muscle stimulators, for example, oxytocic agents, e.g., oxytocin, and the various ergot alkaloids including derivatives and analogs thereof. Therefore, PGE- for example, is useful in place of or in combination with less than usual amounts of these known smooth muscle stimulators, for example, to relieve the symptoms of paralytic ileus, or to control or prevent atonic uterine bleeding after abortion or delivery, to aid in expulsion of the placenta, and during the puerperium. For the latter purpose, the PGE compound is administered by intravenous infusion immediately after abortion or delivery at a dose. in the range about 0.01 to about 50 pg. per kg. of body weight per minute until the desired effect is obtained. Subsequent doses are given by intravenous, subcutaneous, or intramuscular injection or infusion during puerperium in the range 0.01 to 2 mg. per kg. of body weight per day, the exact dose depending on the age, weight, and condition of the patient or animal.

The PGE and PGA compounds are useful as hypotensive agents to reduce blood pressure in mammals, including man. For this purpose, the compounds are administered by intravenous infusion at the rate about 0.01 to about 50 pg. per kg. of body weight per minute,

or in single or multiple doses of about 25 to 500 pg. per kg. of body weight total per day.

The PGE, PGFa and PGF compounds are useful in place of oxytocin to induce labor in pregnant female animals, including man, cows, sheep, and pigs, at or near term, or in pregnant animals with intrauterine death of the fetus from about 20 weeks to term. For this purpose, the compound is infused intravenously at a dose of 0.01 to 50 pg. per kg. of body weight per minute until or near the termination of the second stage of labor, i.e., expulsion of the fetus. These compounds are especially useful when the female is one or more weeks post-mature and natural labor has not started, or 12 to 60 hours after the membranes have ruptured and natural labor has not yet started. An alternative route of administration is oral.

The PGE, PGFa and PGFB compounds are useful for controlling the reproductive cycle in ovulating female mammals, including humans and animals such as monkeys, rats,-rabbits, dogs, cattle, and the like. By the term ovulating female mammals is meant animals which are mature enough to ovulate but not so old that regular ovulation has ceased. For that purpose PGF for example, is administered systemically at a dose level in the range 0.01 mg. to about 20 mg. per kg. of body weight of the female mammal, advantageously during a span of time starting approximately at the'time of ovulation and ending approximately at the time of menses or just prior to menses. lntravaginal and intrauterine are alternative routes of administration. Additionally, expulsion of an embryo or a fetus is accomplished by similar administration of the compound during the first third of the normal mammalian gestation period. I

The PGE and PGF compounds are useful in causing cervical dilation in pregnant and nonpregnant female mammals for purposes of gynecology and obstetrics. In labor induction and in clinical abortion produced by these compounds, cervical dilation is also observed. In cases of infertility, cervical dilation produced by PGE and PGF compounds is useful in assisting sperm movement to the uterus. Cervical dilation by prostaglandins is also useful in operative gynecology such as D and C (Cervical Dilation and Uterine Curettage) where mechanical dilation may cause perforation of the uterus, cervical tears, or infections. It is also useful in diagnostic procedures where dilation is necessary for tissue examination. For these purposes, the PGE and PGF compounds are administered locally or systemically. PGE- 7 for example, is administered orally or vaginally at doses of about to 50mg. per treatment of an adult female human, with from one to five treatments per 24 hour period. PGE is also administered intramuscularly or subcutaneously at doses of about one to 25 mg. per

treatment. The exact dosages for these purposes de-' pend on the age, weight, and condition of the patient or animal.

As mentioned above, the PGE compounds are potent antagonists of epinephrine-induced mobilization of free fatty acids. For this reason, this compound is useful in experimental medicine for both in vitro and in vivo studies in mammals, including man, rabbits, and rats, intended to lead to the understanding, prevention, symptom alleviation, and cure of diseases involving abnormal lipid mobilization and high free fatty acid levels, e.g., diabetes mellitus, vascular diseases, and hyperthyroidism.

The PGA compounds and derivatives and salts thereof increase the flow of blood in the mammalian kidney, thereby increasing volume and electrolyte content of the urine. For that reason, PGA compounds are useful in managing cases of renal disfunction, especially those involving blockage of the renal vascular bed. Illustratively, the PGA compounds are useful to alleviate and correct cases of edema resulting, for example, from massive surface burns, and in the management of shock. For these purposes, the PGA compounds are preferably first administered by intravenous injection at a dose in the range of 10 to 1000 pg. per kg. of body weight or by intravenous infusion at a dose in the range 0.1 to pg. per kg. of body weight per minute until the desired effect is obtained. Subsequent doses are given by intravenous, intramuscular, or subcutaneous injection or infusion in the range 0.05 to 2 mg. per kg. of body weight per day.

The PGE and PGB compounds promote and accelerate the growth of epidermal cells and keratin in animals, including humans, useful domestic animals, pets, zoological specimens, and laboratory animals. For that reason, these compounds are useful to promote and accelerate healing of skin which has been damaged, for example, by burns, wounds, and abrasions, and after surgery. These compounds are also useful to promote and accelerate adherence and growth of skin autografts, especially small, deep (Davis) grafts which are intended to cover skinless areas by subsequent outward growth rather than initially, and to retard rejection of homografts.

For these purposes, these compounds are-preferably administered topically at or near the cite where cell growth and keratin formation is desired, advantageously as an aerosol liquid or micronized powder spray, as an isotonic aqueous solution in the case of wet dressings, or as a lotion, cream, or ointment in combination with the usual pharmaceutically acceptable diluents. In some instances, for example, when there is substantial fluid loss as in the case of extensive burns or skin loss due to other causes, systemic administration is advantageous, for example, by intravenous injection or infusion, separate or in combination with the usual infusions of blood, plasma, or substitutes thereof. Alternative routes of administration are subcutaneous or intramuscular near the site, oral, sublingual, buccal, rectal, or vaginal. The exact dose depends on such factors as the route of administration, and the age, weight, and condition of the subject. To illustrate, a wet dressing for topical application to second and/or third degree burns of skin area 5 to 25 square centimeters would ad.- vantageously involve use of an isotonic aqueous solution containing 1 to 500 ,u.g./ml. of the PGB compound or several times that concentration of the PGE com pound. Especially for topicaluse, these prostaglandins are useful in combination with antibiotics, for example,

gentamycin. neomycin, polymyxic B, bacitracin, spectinomycin, and oxytetracycline, with other antibacteri- I als, for example, mafenide hydrochloride, sulfadiazine, furazolium chloride, and nitrofurazone, and with corticoid steroids, for example, hydrocortisone, prednisolone, methylprednisolone, and fluprednisolone, each of i I thosebeing used in the combination at the usual concentration suitable for its use alone.

SUMMARY OF THE INVENTION I PGE one of the novel compounds of this invention, is.

represented by the formula:

/\/\/O COOH H0 DH The novel compound, 4-oxa-PGE is represented by the formula:

Xll

Some of the novel prostaglandin analogs of this in-- vention have a smaller or greater number of carbon atoms than the formulas shown above, in either the carboxy-terminated side'chain or the alkyl-terminated side chain.

For example, five ofthe novel prostaglandin analogs I of this. invention are represented by the formulas:

and one oxygen atom in that side chain instead of the six carbon atoms and one oxygen atom of the normal X l V 3-oxa structure ofv this invention.

5 In the name of the formula-XVI example, 20-' methyl" indicates that a methyl group replaces a hydrogen on C-20. The methyl-terminated chain of that example therefore has nine carbon atoms.

Where there is branching or fluoro substitution in the 0 side chains, the points of attachment to the side chains A are indicated in the conventional manner, following the I 0 COOH XV atomic numbering of the prostanoic acid skeleton (I).

/ Novel compounds of this invention with epi configuration for the hydroxy at C-IS are so designated by H OH using IS-beta in the name. An example is the name given above for the compound of formula XIV. If 15- beta does not appear in the name, the natural configuration for the C-15 hydroxy, identified as the 8" configuration for POE is to be assumed.

X V The following formulas represent the novel 3-oxa and 4-oxa compounds of this invention in the same optically active form as the naturally occuring prostaglan- Based on its relationship to PGE and prostanoic acid,

the compound of formula XIII is named 3-oxa-4-nor- PGE the compound of formula XIV is named 4-oxa- O 4a,4b-dihomo-l 3,14-dihydro-lS-beta-PGF the /C a am' 500R 1 compound of formula XV is named 3-oxa-l9,20-dinor R R PGA the compound of formula XVI is named 3-oxa- 5,6-dehydro-2O-methyl-PGB and the compound of formula XVII is named 3-oxa-4a-homo-PGF These names for the compounds of formulas XIII to Q XVII are typical of the names used hereinafter for the novel compounds of this invention. These names can better be understood by reference to the structure and numbering system of prostanoic acid (Formula I, above). That formula has seven carbon atoms in the R carboxy-terminated chain and eight carbon atoms in the hydroxy-containing chain. In these names, '3-oxa -O- C-COOR 1 XX and 4-oxa" indicate an oxa oxygen (O in place l of the S-methylene and 4-methylene, respectively of the PG compound. I

The use of nor" or dinor in the names for the H0 2 novel compounds of this invention indicates the ab- Q sence of one or two of the chain carbon atoms and the attached hydrogen atoms. The number or numbers in front of nor, or dinor indicate which of the original prostanoic acid carbon atoms are missing in the named compound. R R

The use of homo" or dihomo as in the names of O l l the formula-XIV and -XVII examples indicate one or 2' q q' two additional carbon atoms in the carboxy-term'inated l side chain. In the name of the formula-XIV example 5 s XXI 4a 4b-dihomo indicates two additional carbon'atoms specifically between the oxygen atom at 4 and the C-5 2 carbon atom. There are, therefore, eight carbon atoms Q XIX , CH -CH=CH-C H 17 18 R las XLVIII to LVII represent 3-oxa and 4-oxa com- 1 pounds of the P68 type. CH -c H w-o-cCOOR UV In formulas XVIII to LVII, R, is hydrogen, alkyl of II one to 12 carbon atoms, inclusive, cycloalkyl of 3 to carbon atoms, inclusive, aralkyl of 7 to 12 carbon atoms, inclusive, phenyl, phenyl substituted with one to Q 3 chloro or alkyl of one to 4 carbon atoms, inclusive, or ethyl substituted in the B-position with 3 chloro, 2 or 3 bromo, or 1,2, or 3 iodo. R is alkyl of one to 10 carbon atoms, inclusive, substituted with zero to 3 fluoro. Q is I R OH or R OH u cn -c -a e I wherein R is hydrogen or alkyl of one to 4 carbon atoms, inclusive. R is alkyl of one to 4 carbon atoms, inclusive, substituted with zero, one, 2 or 3 fluoro. R m 2m' 'f' 1 R R and R are hydrogen or alkyl of one to 4 carbon LV atoms, inclusive. The divalent moiety C,,H repre- H CH -C-R R6 8 sents alkylene of one to 10 carbon atoms, inclusive, ll with one to 5 carbon atoms, inclusive, between Q -CH and -O. The divalent moiety C H represents alkylene of one to 9 carbon atoms, inclusive, with one to 4 carbon atoms, inclusive, between CH and O-. The divalent moiety -C,,H represents alkylene of one to 8 carbon atoms, inclusive, with one, 2, or 3 carbon atoms between CH=CH or C i C- and O. The divalent moiety -C H- represents alkylene of one to 7 carbon atoms, inclusive, with one or 2 carbon atoms between CH= CH or -C E C and O. The divalent moiety C H- represents alkylene of one to 4 carbon atoms, inclusive. The wavy line indicates attachment of the hydroxyl group to the ring in alpha or beta configuration.

CPH2p O-C-COOR1 Formulas XVIII through LVII include the separate isomes wherein Q is either I R; OH or R; OH.

R c=c 9 H H i.e., where the hydroxyl is in either alpha (natural) or beta configuration. Referring to the prostanoic acid atom numbering (formula I above), the point of attachment corresponds to C-l5, and, herein, regardless of the variation in the C-1 to C-7 carboxy chain, these epimers are referred to as C-lS epimers.

Formulas XXVIII through XXXVII wherein the C-9 hydroxyl (following prostanoic acid atom numbering) is attached to the cyclopentane with a wavy line include both PGF and PGF type compounds.

Included in formulas XX, XX], XXX, XXX], XL, XLI, L, and LI are both the cis and the trans compounds with respect to the C-5 to C-6 double bond in the carboxyl-terminated side chain. In all of the compounds containing the C -to-C, double bond, that double bond is in trans configuration, and the chain containing that moiety is attached to the cyclopentane ring in beta configuration in compounds encompassed by formulas XVIII to XLVII.

The novel 3-oxa and 4-oxa compounds of this invention include racemic compounds and both optically active enantiomeric forms thereof. As discussed herein- 557 0-C C-COOR Formulas XVIII to XXVII represent 3-oxa and 4-oxa compounds of the PGE type. Formulas XXVIII to XXXVII represent 3-oxa and 4-oxa compounds of the PGF type. Formulas XXXVIII to- XLVII represent 3-oxa and 4-oxa compounds of the PGA type. Formuabove, two structural formulas are required to define accurately these racemic compounds. The formulas as drawn herein are intended to represent compounds with the same configuration as the naturally-occurring prostaglandins. However, for convenience in the charts herein only a single structural formulas is used, for example in Chart E, to define not only the optically active form but also the racemic compounds which generally undergo the same reactions.

Formula XVIII represents 3-oxa-PGE (formula XI hereinabove) when C H is -(CH Q is R R and R are hydrogen, and R is n-pentyl.

With regard to formulas XVIII to LVII, examples of alkyl of one to 4 carbon atoms, inclusive, are methyl, ethyl, propyl, butyl, and isomeric forms thereof. Examples of alkyl of one to 8 carbon atoms, inclusive, are those given above, and pentyl, hexyl, heptyl, octyl, and isomeric forms thereof. Examples of alkyl of one to 12 carbon atoms, inclusive, are those given above, and nonyl, decyl, undecyl, dodecyl, and isomeric forms thereof. Examples of cyeloalkyl of 3 to 10 carbon atoms,.inclusive, which includes alkyl-substituted cycloalkyl, are cyclopropyl, 2-methylcyclopropyl, 2,2- dimethylcyclopropyl, 2,3-diethylcyclopropyl, 2-butylcyclopropyl, cyclobutyl, Z-methylcyclobutyl, 3-propylcyclobutyl, 2,3,4-triethylcyclobutyl, cyclopentyl, 2,2- dimethylcyclopentyl, 3-pentylcyclopentyl, 3-tert-butylcyclopentyl, cyclohexyl, 4-tert-butylcyclohexyl, 3-isopropylcyclohexyl, 2,2-dimethylcyclohexyl, eycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Examples of aralkyl of 7 to 12 carbon atoms, inclusive, are benzyl, phenethyl, l-phenylethyl, Z-phenylpropyl, 4- phenylbutyl, 3-phenylbutyl, Z-(I-naphthylethyl), and I-(Z-naphthylmethyl), Examples of phenyl substituted by one to 3 chloro oralkyl of one to 4 carbon atoms, inclusive, are p-chlorophenyl, m-chlorophenyl, ochlorophenyl, 2,4- dichlorophenyl, 2,4,6-trichlorophenyl, p-tolyl, m-tolyl, o-tolyl, p-ethylphenyl, p-tert-butylphenyl, 2,5-dimethylphenyl, 4-chloro-2-methylphenyl, and 2,4-diehloro-3-methylphenyl.

Examples of alkyl of one to 10 carbon atoms, inclusive, substituted with one to 3 fluoro, are fluoromethyl, 2-fluoroethyl, 2-fluorobutyl, 3-fluorobutyl, 4-fluorobutyl, S-fluoropentyl, 4-fluoro-4-methylpentyl, 3- fluoroisoheptyl, 8-fluorooctyl, 3,4-difluorobutyl, 4,4- difluoropentyl, 5,5-difluoropentyl, 5,5,5-trifluoropen tyl, and 10,10,10-trifluorodecyl.

Examples of alkylene within the various scopes of C,I-I C I-i C I-I C l-I and C H as those are defined above, are methylene, ethylene, trimethylene, tetramethylene, pentamethylene, and those alkylene with one or more alkyl substituents on one or more carbon The novel formula XVIII-XXVI! PGE-type 3-oxa and 4-oxa compounds, the novel formulas XXVIlI-XXXVII PGFa -type and PGFB -type 3-oxa and 4-oxa compounds, the novel formula XXXVIII-XLVII pGA-type 3-oxa and 4-oxa compounds, and the novel formula XLVIII-LVII PGB-type 3-oxa and 4-oxa compounds, and their racemic forms, each cause the biological re- 20 sponses described above for the PGE, PGF a PGA, and PCB compounds, respectively, and each of these novel compounds is accordingly useful for the! above-described corresponding purposes, and is used for those purposes in the same manner as described above.

The known PGE, PGF PGFB activity. Moreover, for many applications, these known prostaglandins have an inconveniently short duration 7 of biological activity. In striking contrast, the novel for mula XVIII-to-LVII analogs and their racemic forms I are substantially more specific with regard'to potency in causing prostaglandin-like biological responses, and have a substantially longer duration of biological activity. Therefore, each of these novel prostaglandin analogs is useful in place of one of the. corresponding. above-mentioned known prostaglandins for at least one of the pharmacological purposes indicated above for.

the latter, and is surprisingly and unexpectedly more useful for that purpose because it has a different and narrower spectrum of biological activity than the known prostaglandin, and therefore is more specific in its activity and causes smaller and fewer undesired side effects than the known prostaglandin. Moreover, because of its prolonged activity, fewer and smallerdoses of the novel prostaglandin analog can frequently be used to attain the desired result.

To obtain the optimum combination of biological potency specificity and duration of activity, certain com pounds within the scope of formulas XVIII to LVII are preferred. For example, it is preferred that the carboxyterminated chain in each formula contain a chain of six atoms between the carboxyl and the cyclopentane ring.

One of those six atoms will be the oxa atom and the 5 other five will be carbonatoms. Accordingly and with reference to formulas XVIII to LVII, it is preferred that 3 -C,,H2,.- represent a 3-carbon divalentchain, that C,,,H --represent a Z-carbon divalent chain, and

that C,,H represent a divalent carbon atom.

These preferences do not exclude additional carbon atoms (alkyl groups) as branching.

A seven-atom carboxyl terminated chain is notincluded in the compounds of formulas XXI, XXIII, x

XXVII, XXXI, XXXIII, XXXVII, XLI, XLIII, XLVII,

LI, LI", and LVII, i.e., formulas wherein the carboxy terminated side chain is 4-oxaand contains a carboncarbon double or triple bond. In each of those compounds, the q of C,,I-I is at least one, and at least seven atoms, one oxygen (oxa) and six carbons, are present between the carboxyl and the cyclopentane ring. In these compounds, the preference is for that minimum chain, i.e., q is one.

Another preference for the compounds of formulas XVIII to LVII is that R R R R and R be hydrogen or methyl. All of those R groups can be hydrogen, all;

can be methyl, or there can be any of the possiblecombinations of hydrogen andimethyl. It is especially preferred for prolonged duration of biological activity that both R and R be methyl, and/or that R be methyl.

Certain variations in the nature of R in formulas XVIII-XXV, XXVIII-XXXV, XXXVIIIXI.V, and

XLVIlI-LV are especially important. In the knownv f prostaglandins, e.g., PGE the portion of the molecule corresponding to R in the above-mentioned formulas is pentyl. It is preferred that R be pentyl in formulas XVIII-XXV, XXVlII-XXXV, XXXVIl-XLV, and XLVlIl-LV. It is also preferred that R be straight chain alkyl of 3 to 7 carbon atoms, inclusive, with or without a fluoro substituent at the l-position e.g., CHF(CI-I CH wherein g is one to 5. Alternately, R is represented by wherein R is hydrogen or fluoro and g is one, 2, 3, 4, or 5. Pentyl and l-fluoropentyl are, of course, included in this preference.

In compounds of formulas XXVI, XXVII, XXXVI, XXXVII, XLVI, XLVII, LVI, and LVII, it is preferred that G l-I be methylene and that R be ethyl.

Another advantage of the novel compounds of this invention, especially the preferred compounds defined hereinabove, compared with the known prostaglandins, is that these novel compounds are administered effectively orally, sublingually, intravaginally, buccally, or rectally, in addition to usual intravenous, intramuscular, or subcutaneous injection or infusion methods indicated above for the uses of the known prostaglandins. These qualities are advantageous because they facilitate maintaining uniform levels of these compounds in the body with fewer, shorter, or smaller doses, and make possible self-administration by the patient.

The PGE, PGF PGF PGA, and PGB type 3-oxa and 4-oxa compounds encompassed by formulas XVIII to LVII including the special classes of compounds described above, are used for the purposes described above in the free acid form, in ester form, or in pharmacologically acceptable salt form. When the ester form is used the ester is any of those within the above definition of R However, it is preferred that the ester be alkyl of one to 12 carbon atoms, inclusive. Of those alkyl, methyl and ethyl are especially preferred for optimum absorption of the compound by the body or experimental animal system; and straight-chain octyl, nonyl, decyl, undecyl, and dodecyl are especially preferred for prolonged activity in the body or experimental animal.

Pharmacologically acceptable salts of these formula XVIII-to-LVII compounds useful for the purposes described above are those with pharmacologically acceptable metal cations, ammonium, amine cations, or quaternary ammonium cations.

Especially preferred metal cations are those derived from the alkali metals, e.g., lithium,- sodium and potassium, and from the alkaline earth metals, e.g., magnesium and calcium, although cationic forms of other metals, e.g., aluminum, zinc, and iron, are within the scope of this invention.

Pharmacologically acceptable amine cations are those derived from primary, secondary, or tertiary amines. Examples of suitable amines are methylamine, dimethylamine, trimethylamine, ethylamine, dibutylamine, triisopropylamine, N-methylhexylamine, decylamine dodecylamine, allylamine, crotylamine, cyclopentylamine, dicyclohexylamine, benzylamine, dibenzylamine, a-phenylethylamine, B-phenylethylamine, etheylenediamine, diethylenetriamine, and like aliphatic, cycloaliphatic, and araliphatic amines containing up to and including about 18 carbon atoms, as well as heterocyclic amines, e.g., piperidine, morpholine, pyrrolidine, piperazine, and lower-alkyl derivatives thereof, e.g., l-methylpiperidine, 4-ethylmorpholine, l-isopropylpyrrolidine, Z-methylpyrrolidine, 1,4- dimethylpiperazine, 2-methylpiperidine, and the like, as well as amines containing water-solubilizing or hydrophilic groups, e.g., mono-, di-, and triethanolamine, ethyldiethanolamine, N-butylethanolamine, Z-aminol-butanol, 2-amino-2-ethyl-l,3-propanediol, 2-amino- Z-methyl-l-propanol, tris-(hydroxymethyl)aminomethane, N-phenylethanolamine, N-(p-tert-amylphenyl)- diethanolamine, galactamine, N-methylglucamine, N- methylglucosamine, ephedrine, phenylephrine, epinephrine, procaine, and the like.

Examples of suitable pharmacologically acceptable quaternary ammonium cations are tetramethylammonium, tetraethylammonium, benzyltrimethylammonium, phenyltriethylammonium, and the like.

The 3-oxa and 4-oxa PGE, PGF PGF PGA, and PGB type compounds encompassed by formulas XVIII to LVII including the special classes of compounds described above, are also used for the purposes described above in free hydroxy form or in the form wherein the hydroxy moieties are transformed to lower alkanoate moieties, e.g., OH to -OCOCH Examples of lower alkanoate moieties are acetoxy, propionyloxy, butyryloxy, valeryloxy, hexanoyloxy, heptanoyloxy, ,octanoyloxy, and branched chain alkanoyloxy isomers of those moieties. Especially preferred among these alkanoates for the above described purposes are the acetoxy compounds. These free hydroxy and alkanoyloxy compounds are used as free acids, as esters, and in salt form all as described above.

As discussed above, the compounds of formulas XVIII to LVII are administered in various ways for various purposes; e.g., intravenously, intramuscularly, subcutaneously, orally, intravaginally, rectally, bucally, sublingually, topically, and in the form of sterile implants for prolonged action. For intravenous injection or infusion, sterile aqueous isotonic solutions are preferred. For that purpose, it is preferred because of increased water solubility that R, in the formula XVIII- to-LVII compound be hydrogen or a pharmacologically acceptable cation. For subcutaneous or intramuscular injection, sterile solutions or suspensions of the acid, salt, or ester form in aqueous or non-aqueous media are used. Tablets, capsules, and liquid preparations such as syrups, elixirs, and simple solutions, with the usual pharmaceutical carriers are used for oral sublingual administration. For rectal or vaginal administration, suppositories prepared as known in the art are used. For tissue implants, a sterile tablet or silicone rubber capsule or other object containing or impregnated with the substance is used.

The 3-oxa and 4-oxa PGE, PGF PGF PGA, and PGB type compounds encompassed by formulas XVIII to LVII are produced by the reactions and procedures described and exemplified hereinafter.

The various 3-oxa and 4-oxa PGF a -type and PGF ,9 -type compounds encompassed by formulas XXVIlI-XXXVII are prepared by carbonyl reduction of the corresponding PGE type compounds encompassed by formulas XVIII-XXVII. For example,'carbonyl reduction of 3-oxa PGE gives a mixture of 3-oxa PGF, 0: and 3-oxa PGF These ring carbonyl reductions are carried out by methods known in the art for ring carbonyl reductions of known prostanoic acid derivatives. See, for example, Bergstrom et al., Arkiv Kemi 19, 563 (1963), Acta the separation of analogous pairs of known isomeric prostanoic acid derivatives. See, for example, Bergstrom et al., cited above, Granstrom et al., J. Biol. Chem. 240, 457 (1965), and Green et al., J. Lipid Research 5, 117 (1964). Expecially preferred as separation methods are partition chromatographic procedures, both normal and reversed phase, preparative thin layer chromatography, countercurrent distribution procedures, and column chromatography.

The various 3-oxa and 4-oxa PGA-type compounds encompassed by formulas XXXVIIl-XLVII are prepared by acidic dehydration of the corresponding PGE type compounds encompassed by formulas XVIII-XX- VII. For example, acidic dehydration of 3-oxa PGE gives 3-oxa PGA,.

These acidic dehydrations are carried out by methods known in the art for acidic dehydrations of known prostanoic acid derivatives. See, for example, Pike et al., Proc. Nobel Symposium 11, Stockholm (1966), Interscience Publishers, New York, pp. 162-163 (1967); and British Specification 1,097,533. Alkanoic acids of 2 to 6 carbon atoms, inclusive, especially acetic acid, are preferred acids for this acidic dehydration. Dilute aqueous solutions of mineral acids, e.g., hydrochloric acid, especially in the presence of a solubilizing diluent, e.g., tetrahydrofuran, are also useful as reagentsfor this acidic dehydration, although these reagents may cause partial hydrolysis of an ester reactant.

The various 3-oxa and 4-oxa PGB-type compounds encompassed by formulas XLVIl-LVII are prepared by basic dehydration of the corresponding PGE type compounds encompassed by formulas XVIII-XXVII, or by contacting the corresponding PGA compounds encompassed by formulas XXXVIII-XLVII with base. For example, both 3-oxa PGE, and 3-oxa PGA, give 3-oxa PGB, on treatment with base.

These basic dehydrations and double bond migra tions are carried out by methods known in the art for similar reactions of known prostanoic acid derivatives. See, for example, Bergstrom et al., J. Biol. Chem. 2148,3555 (1963). The base is any whose aqueous solution has pI-I greater than 10. Preferred bases are the alkali metal hydroxides. A mixture of water and sufficient of a water-miscible alkanol to give a homogeneous reaction mixture is suitable as a reaction medium. The POE-type or PGA-type compound is maintained in such a reaction medium until no further PGB-type compound is formed, as shown by the characteristic ultraviolet light absorption near 278 nm for the PCB type compound.

The various transformations of 3-oxa and 4-oxa PGE type compounds of formulas XVIII to XXV to the corresponding 3-oxa and 4-oxa PGFQ, PGF PGA, and PGB type compounds are shown in Chart A, wherein 0, R R and are as definedabove, and wherein A is CH -CH or trans-CH=CH, Q is above, with the proviso that V is C,,H ,l-OCR CH CH The 3-oxa and 4-oxa PGE type coma PGF; B PGA and PGB compounds by analogous reactions.

The various 3-oxa and 4-oxa dihydro-PGE dihydro- PGF dihydro-PGF, B dihydro-PGA,, and dihydro-PGB type compounds encompassed by formulas XXIV, XXV, XXXIV, XXXV, XLlV, XLV, LIV, and LV are prepared by carbon-carbon double bond reduction of the corresponding PGE, PGF PGF 3 PGA, and PCB type compound containing a trans double bond in the hydroxy-containing side chain. A cis or trans double bond or an acetylenic bond can also be present in the carboxy-terminated side chain of the unsaturated reactant, and will be reduced at the same time to -CH CH For example, dihydro-3-oxa- PGE is produced by reduction of 3-oxa-PGE 3-oxa- PGE or 5,6-dehydro-3-oxa-PGE These reductions are carried out by reacting the unsaturated PGE, PGF PGF PGA, or PGB type compound with diimide, following the general procedure described by van Tamelen et al., J. Am. Chem. Soc., 83, 3726 (1961). See also Fieser et al., Topics in Organic Chemistry, Reinhold Publishing Corp., New York, pp. 432-434 (1963) and references cited therein. The unsaturated acid or ester reactant is mixed with a salt of azodiformic acid, preferably an alkali metal salt such as the disodium or dipotassium salt, in the presence of an inert diluent, preferably a lower alkanol such as methanol or ethanol, and preferably in the absence of substantial amounts of water. At least one molecular equivalent of the azodiformic acid salt is used for each multiple bond equivalent of the unsaturated reactant. The resulting suspension is then stirred, preferably with exclusion of oxygen, and the mixture is made acid, advantageously with a carboxylic acid such as acetic acid. When a reactant wherein R is hydrogen is used, that carboxylic acid reactant also serves to acidify an equivalent amount of the azodiformic acid salt. A reaction temperature in the range about to about 40 C. is usually suitable. Within that temperature range, the reaction is usually complete within less than 24 hours. The desired dihydro product is then isolated by conventional methods, for example, evaporation of the diluent, followed by separation from inorganic materials bysolvent extraction.

In the case of the 3-oxa and 4-oxa unsaturated PGE, PGFQ and PGF 5 type reactants, the reductions to the corresponding 3-oxa and 4-oxa dihydro-PGE dihydro-PFG and dihydro-PGF 3 compounds are also carried out by catalytic hydrogenation. For that purpose, palladium catalysts, expecially on a carbon H carrier, are preferred. It is also preferred that the hydrogenation be carried out in the presence of an inert liquid diluent, for example, methanol, ethanol, dioxane, ethyl acetate, and the like. Hydrogenation pressures ranging from about atmospheric to about psi, and hydrogenation temperatures ranging from wherein C,,H C l-l R R R and R are as defined above.

55 about 0 to about C. are preferred. The resulting CHART B di i ml de or hydrogen catalyst ,cna-w-cooa,

diimide CHART B -Continued cii -w-coort H di imide These diimide reductions and catalytic hydrogenations to produce the same novel 3-oxa and 4-oxa dihydro compounds of this invention from the corresponding 3-oxa and 4-oxa PGE PGF PGF PGH and P68 type compounds and also from the corresponding compounds with a trans-ethylenic or an acetylenic linkage in place of the cis-ethylenic linkage in the carboxyl-terminated side chain, are shown in Chart C, wherein Q, R,,'R and are as defined above, U is cis-CH=Cl-l, trans-CH=CH--, or --C EC, and Y is C,,H ,,OCR -,R or C,,H -O-CR R CR R wherein p, q, R R R and R are as defined above.

The 3-0xa and 4-oxa compounds of, the PGE PGF PGF PGA and PGB type wherein the carbon-carbon double bond in the carboxy-terminated side chain is in cis configuration are prepared by reduction of the corresponding acetylenic 3-oxa and 4-oxa compounds, i.e., those with a carbon-carbon triple bond in place of said carbon-carbon double bond. For

that purpose, there are used any of the known reducing agents which reduce an acetylenic linkage to a cis-ethylenic linkage. Especially preferred for that purpose are diimide or hydrogen and a catalyst, for example, palladium (5%) on barium sulfate, especially in the presence of pyridine. See Fieser et al., Reagents for Organic Synthesis, pp. 566-567, John Wiley, & Sons, lnc., New York, N.Y. (1967). These reductions are shown in Chart D, wherein Q,R,, R and are as defined above, and Y is C,,H ,,O-CR R or C,,H --O-CR R CR R These 3-oxa and 4-oxa cis compounds of the PGE PGF PGF B PGA and P63 type are also prepared as described hereinafter.

CHART c CH2-U-Y-CO0R1 ll Q :di imi de or 2 hydrogen catalyst di imi de= or hydrogen 4- catalyst /CH2-CEC-Y-C00R1 ll Q The 3-oxa and 4-oxa PGE type compounds of formulas XVIII to XXIII except wherein R is hydrogen, and the 3-oxa and 4-oxa PGA type compounds of formulas XXXVIII to XLIII except wherein R is hydrogen are prepared by the series of reactions shown in Chart E, wherein Q, R and V are as defined above, R and R are alkyl of one to 4 carbon atoms, inclusive, R is the same as the above definition of R except'that R does not include hydrogen, R3 is alkyl of one to carbon atoms, inclusive, and indicates exo or endo configuration with respect to the moiety attached to the cyclopropane ring.

The 3-oxa and 4-0xa PGI-E type compounds of formulas XVIII and XIX, the 3-oxa and 4-oxa 5,6-dehydro-PGE type compounds of formulas XXII and XXIII, the 3-oxa and 4-oxa PGA type compounds of formulas XXXVIII and XXXIX, and the 3-oxa and 4-oxa 5,6-dehydro-PGA type compounds of formulas XLII and XLIII are also prepared by the series of reactions shown in Chart F, wherein Q, R R R and R are as defined above, Z is C,,H ,,--OCR R C,,,H ,,,-OCR R CR R --C E C-C,,H- -OCR 'R or -C E CC,,H ,,OCR R CR R and indicates exo or endo configura- 32 tion with respect to the moiety attached to the propane ring.

It should be observed regarding the series cycloof reactions shown in Charts E and F, that the reactions start- I ing with glycol LX in Chart E are similar to the rea'cI- tions starting with glycol LXVII in Chart FQThe onlyi differences here are the definitions of the divalent moieties V (Chart E) and Z (Chart F). V includes satu:

rated, cis and trans ethylenic, and acetylenic divalent moieties. Z is limited to the saturated and acetylenic divalent moieties encompassed by V.

LLVI i j 35 CHART F continued CHE-Z-COOR 1o LXVI l 13 2 so S02R13 HO H ,CH2 Z-COOR LXX CH- H-Rz I HO OSQ2R1S In other words, final 3-oxa and 4-oxa PGE type compounds of formula LXII (Chart E) encompass compounds of formulas XVIII to XXIII. Final 3-oxa and 4-oxa PGA type compounds of formula LXIII (Chart E) encompass compounds of formulas XXXVIII to XLIII. On the other hand, final 3-oxa and 4-.oxa PGE type compounds of formula LXIX (Chart F) encompass only compounds of formulas XVIII, XIX, XXII, and XXIII, and final 3-oxa and 4-oxa PGA type compounds of formula LXX (Chart F) encompass only compounds of formulas XXXVIII, XXXIX, XLII and XLIII.

As will subsequently appear, an acetylenic intermediate of formula LIX, formula LX, or formula LXVII is transformed by reduction to the corresponding cis or trans ethylenic intermediates of formulas LIX or LX, and an acetylenic intermediate of formulas LIX, LX, or LXVII, or a cis or trans ethylenic intermediate of formulas LIX or LX is transformed by reduction to the corresponding saturated intermediate of formulas LIX, LX, or LXVII.

The initial bicyclo-ketone reactant of formula LXV in Chart F is also used as an initial reactant to produce the initial bicyclo-ketone cyclic ketal reactant of formula LVllI in Chart E. The reactions of Chart G will produce cyclic ketal LVIII. Therein THP is tetrahydropyranyl, and (15 is phenyl.

The bicyclo-ketone reactant of formula LXV exists in four isomeric forms, exo and endo with respect to I the attachment of the CH=CHR moiety, and cis and trans with respect to the double bond inthat moiety. Each of those isomers separately or various mixtures thereof are used as reactants according to this invention to produce substantially the same final 3foxa or I 4-oxa PGE or PGA type product mixture.

CHART G OTHP k s Q)! LXXI i H L a I Via several ste 0 p5 Lxv CH=CH-R2 O. {l/i LXXI IH-(IZH-RE 0H 0H LVI l l lcH-ilzH-Rz o o t R1}R12 The process for preparing either the exo or endo configuration of the formula-LXV bicyclo-ketone is known to the art. See Belgian Pat. No. 702,477; reprinted in Farmdoc Complete Specifications, Book 714, No. 30,905, page 313, Mar. 12, 1968. See West Germany Offenlegungsschrift No. 1,937,912; reprinted in Farmdoc Complete Specifications, Book No. 14, No. 6869 R, Week R Mar. 18, 1970.

In said Belgian Pat. No. 702,477, a reaction sequence capable of forming exo ketone LXV is as follows: The hydroxy of 3-cyclopentenol is protected, for example, with a tetrahydropyranyl group. Then a diazoacetic acid ester is added to the double bond to give an exoendo mixture of a bicyclo[3.1.0]hexane substituted at 3 with the protected hydroxy and at 6 with a esterified carboxyl. The exo-endo mixture is treated with a base to isomerize the endo isomer in the mixture to more of the exo isomer. Next, the carboxylate ester group at 6 is transformed to an aldehyde group, Cl-lO. Then, said aldehyde group is transformed by the Wittig reaction, in this case to a moiety of the formula CH= CH-R which is in exo configuration relative to the bicyclo ring structure. Next, the protective group is removed to regenerate the 3-hydroxy which is then oxidized, for example, by the Jones reagent, i.e., chromic acid (see J. Chem. Soc. 39 (1946)), to give said exo ketone LXV.

Separation of the cis-exo and trans-exo isomers of LXV is described in said Belgian Pat. No. 702,477. However, as mentioned above, that separation is usually not necessary since the cis-trans mixture is useful as a reactant in the next process step.

The process described in said Belgian Pat. No. 702,477 producing the exo form of bicyclo-ketone LXV uses, as an intermediate, the exo form of a bicyclo [3.1.0]hexane substituted at 3 with a protected hydroxy, e.g., tetrahydropyranyloxy, and at 6 with an esterified carboxyl. When the corresponding endo compound is substituted for that exo intermediate, the process in said Offenlegungsschrift No. 1,937,912 leads to ,the endo form of bicyclo-ketone LXV. That endo com- .pound to be used has the formula:

COOCHa LXX l V Compound LXXIV is prepared by reacting endo-bicyclo[3.l.0]-hexane-3-ol-6-carboxylic acid methyl ester which is then reacted with dihydropyran in the presence of a catalytic amount of POCl to give the desired compound. This is then used as described in said Offenlegungsschrift No. 1.937,9l2 to product the endo form of bicyclo-ketone LXV.

As for exo LXV, the above process produces a mixture of endo-cis and endo-trans compounds. These are separated as described for the separation of exo-cis and exo-trans LXV, but this separation is usually not necessary since, as mentioned above, the cis-trans mixture is useful as a reactant in the next process step.

In the process of said Belgian patent and said Offenlegungsschrift, certain organic halides, e.g., chlorides and bromides, are necessary to prepare the Wittig reagents used to generate the generic moiety, -CH=A CHR of bicyclo-ketone LXV. These organic chlorides and bromides R -CH -Cl and R CH Br, are known in the art or can be prepared by methods known in the art.

To illustrate the availability of these organic chlorides consider first the above-described 3-oxa and 4-oxa PGE-type compounds of formulas XVIIl to XXVII wherein G is alkyl of one to 10 carbon atoms, inclusive, substituted with zero, one, 2, or 3 fluoro.

For those products wherein R is alkyl of one to 10 carbon atoms, substituted with zero to 3 fluoro atoms, there are available the monohalo hydrocarbons, e.g., bromo-(or chloro-)methane, -ethane, -propane, -pentane, -octane, and -decane; and the monohalofluorohydrocarbons, e.g., CH FCl, CH FCH Br, CHF CH Cl, CF CH Br, F(CH Br, CH CF CH Cl, CF (Cl-l Br,

CH (Cl-l CF (CH Cl-l Cl, as described in Aliphatic Fluorine Compounds, A. M. Lovelace et al., Am. Chem. Soc. Monograph Series 1958, Reinhold PUbl. Corp. Those halides not available are prepared by methods known in the art by reacting the corresponding primery alcohol R -CH OH with PCI;,, PBr or any of the other halogenating agents useful for this purpose. Available alcohols include CH CH(CF )CH Ol-l, (CH )2CHCl-l CH Ol-l, (Cl-l CCl-1 OH, CF CH(CH )CH CH OH for example. For those halides of the formula R CH l-lal wherein Hal is chloro or bromo R is R (CH d being one, 2, 3, or 4, and R being isobutyl, tert-butyl, 3,3-difluorobutyl, 4,4-difluorobutyl, or 4,4,4-trifluorobutyl, the intermediate alcohols are prepared as follows.

in the case of R being isobutyl or tert-butyl, known alcohols are converted to bromides, thence to nitriles with sodium cyanide, thence to the corresponding carboxylic acids by hydrolysis, and thence to the corresponding primary alcohols by reduction, e.g. with lithium aluminum hydride, thus extending the carbon chain one carbon atom at a time until all primary alcohols are prepared.

In the case of R being 3,3-difluorobutyl, the necessary alcohols are prepared from keto carboxylic acids of the formula, CH3-cO-(CH2)rCOOH, wherein r is 2, 3,4, 5, or 6. All of those acids are known. The methyl esters are prepared and reacted with sulfur tetrafluoride to produce the corresponding Gil -CF- --(CH )r--COOCH compounds, which are then reduced with lithium aluminum hydride to Cri -CF- -(CH ),--CH OH. These alcohols are then transformed to the bromide or chloride by reaction with PEI-3 0r In the case of R being 4,4-difluorobutyl, the initial reactants are the known dicarboxylic acids, HOO- C-(CH ),COOH, wherein f is 3, 4, 5, 6, or 7. These dicarboxylic acids are esterified to CH OOC(CH ),COOCH and then half-saponified, for example with barium hydroxide, to give HOOC--(CH );-COOCH The free carboxyl group is transformed 

1. AN OPTICALLY ACTIVE COMPOUND OF THE FORMULA:
 2. A racemic compound according to claim
 1. 3. An optically active compound according to claim
 1. 4. A compound according to claim 3 wherein CnH2n is straight chain alkylene of one to 5 carbon atoms, inclusive.
 5. A compound according to claim 4 wherein CnH2n is trimethylene.
 6. A compound according to claim 5 wherein R5 and R6 are hydrogen or methyl, being the same or different.
 7. A compound according to claim 6 wherein R5 and R6 are hydrogen.
 8. A compound according to claim 7 wherein R2 is pentyl.
 9. A compound according to claim 8 wherein Q is
 10. A compound according to claim 8 wherein Q is
 11. A compound according to claim 10 wherein R1 is hydrogen or alkyl of one to 4 carbon atoms, inclusive, including the pharmacologically acceptable salts thereof when R1 is hydrogen.
 12. A compound according to claim 11 wherein R1 is hydrogen or alkyl of one to 4 carbon atoms, inclusive.
 13. A compound according to claim 12 wherein R1 is hydrogen, methyl, or ethyl.
 14. 3-Oxa-PGB1a compound according to claim
 13. 15. 3-Oxa-PGB1, methyl ester, a compound according to claim
 13. 16. 15-Methyl-3-oxa-PGB1, a compound according to claim
 13. 17. 15-Methyl-3-oxa-PGB1, methyl ester, a compound according to claim
 13. 18. An optically active compound of the formula:
 19. A racemic compound according to claim
 18. 20. An optically active compound according to claim
 18. 21. A compound according to claim 20 wherein CnH2n is straight chain alkylene of one to 5 carbon atoms, inclusive.
 22. A compound according to claim 21 wherein CnH2n is trimethylene.
 23. A compound according to claim 22 wherein R5 and R6 are hydrogen or methyl, being the same or different.
 24. A compound according to claim 23 wherein R5 and R6 are hydrogen.
 25. A compound according to claim 24 wherein R2 is pentyl.
 26. A compound according to claim 25 wherein Q is
 27. A compound according to claim 25 wherein Q is
 28. A compound according to claim 27 wherein R1 is hydrogen or alkyl of one to 4 carbon atoms, inclusive, including the pharmacologically acceptable salts thereof when R1 is hydrogen.
 29. A compound according to claim 28 wherein R1 is hydrogen or alkyl of one to 4 carbon atoms, inclusive.
 30. A compound according to claim 29 wherein R1 is hydrogen, methyl, or ethyl.
 31. A compound according to claim 30 wherein the C-5 to C-6 double bond in the carboxyl-terminated side chain is in the cis configuration.
 32. 3-Oxa-PGB2, a compound according to claim
 31. 33. 3-Oxa-PGB2, methyl ester, a compound according to claim
 31. 34. 15-Methyl-3-oxa-PGB2, a compound according to claim
 31. 35. 15-Methyl-3-oxa-PGB2, methyl ester, a compound according to claim
 31. 36. An optically active compound of the formula:
 37. An optically active compound of the formula:
 38. An optically active compound of the formula: 